Practical%20Techniques%20for%20Implementing%20Emergent%20Gameplay

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Practical Techniques for Implementing Emergent
GameplayWould the Real EmergentGameplay Please
Stand Up?

• Randy Smith
• rsmith_at_ionstorm.com

Harvey Smith hsmith_at_ionstorm.com
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Intro

• Harvey SmithDeus Ex/Invisible War
• Randy SmithThief 1/2/3
• Ion Storm aesthetic goals
• Improvisational (player-authored) gameplay
• Benefits from large gameplay possibility space
• Emergence provides more explorable space

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Our Topic

• How to Add Meaningful Emergence to Video Games
• Topics that have been covered elsewhere
• History of Emergence
• Emergence and Narrative
• Emergence and Uncertainty
• Benefits and Costs/Risks of Emergence

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Focus

• Less Theoretical, More Practical
• Related to modern game system design
• Skewed toward large-scale action games
• Emergence within a game system context
• No player psychology, social influence, etc.
• Focus on the system space of game
• Power-ups, Weapons, Tools, Monsters

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Disclaimers

• Emergent gameplay isn't necessary to design good
  games
• No holy wars, despite the provocative title of
  the presentation

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Takeaway

• A practical approach to creating meaningful
  emergence in your own game designs.
• You are a game designer
• You design game systems
• You want to focus on emergent gameplay
• How do you accomplish this?

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Outline

• Preamble
• Intro to Emergence
• Creating Emergence
• Creating Mechanics that result in emergent game
  dynamics
• Qualifying Emergence
• Creating emergent gameplay that results in
  meaningful game aesthetics
• Wrapping Up
• Q A

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I Intro to Emergence

• Definitions
• Vocabulary
• Examples

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A Typical Real-World Definition

• A discernable, higher-level behavior of a system
  which is not immediately obvious by looking at
  the low-level rules that govern the systems
  behavior.
• lets look at an example of real-world emergence

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Global Warming
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Global Warming
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Global Warming
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Global Warming
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Global Warming
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MDA Framework

• A rules-oriented approach to game design
• MechanicsThe rules of the game
• DynamicsReal-time rules interactions
• AestheticsHuman emotional responses

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Emergence in Video Games(our definition)

• A second order game Dynamic created by the
  interaction of first order game Mechanics.

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Example 01 GTA3

• Player accidentally flips his car, which
  explodes, injuring nearby pedestrians who begin
  to attack him
• Player takes a jump ?
• Car flips and lands upside down ?
• Car explodes ?
• Nearby pedestrians are injured by explosion ?
• Pedestrians begin to attack player

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Example 01 GTA3

• Player accidentally flips his car, which
  explodes, injuring nearby pedestrians who begin
  to attack him
• Player takes a jump ?
• Car flips and lands upside down ?
• Car explodes ?
• Nearby pedestrians are injured by explosion ?
• Pedestrians begin to attack player
• Note that there is no explicit Mechanic
  describing this behavior

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Example 02 Tactical Shooter

• Indirectly Connected game Mechanics
• Gas barrels Leak poison when ruptured
• Poison Kills enemies and players
• Bullets Kill enemies, and Rupture gas barrels
• Weapons Fire bullets when dropped
• Enemies Fire bullets, and Drop weapons on death
• Player shoots guard ? guard drops gun ? gun goes
  off when it hits the ground ? bullets rupture
  barrel ? poison leaks out ? poison kills other
  enemies

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Example 03 Thief

• In order to injure a nearby guard, player ignites
  an oil puddle by knocking a candle off a table
• Player throws a box at a table ?
• Table wobbles ?
• Candle falls off table ?
• Candle falls into oil puddle ?
• Oil puddle ignites ?
• Nearby guard is injured by the flames

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MDA Framework
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MDA Applied to Emergence

• Mechanics
• The rules of the game
• You modify Mechanics to alter emergent
  interactions
• Dynamics
• Real-time interactions between Mechanics
• Mechanics connecting to each other
• Where emergence happens
• Aesthetics
• Human emotional responses
• Wider exploration space, emergent narrative

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II Creating Emergence

• Quantitative
• Mechanics
• Connecting Mechanics Together
• Relevant Technology
• Populating the world with Mechanics

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Where Mechanics Live

• Power-ups
• When guns hit the ground, they fire off bullets
• Environmental Objects
• When barrels are damaged, they release poison
  gas
• Simulations
• Cars can flip upside down when they land from
  jumps
• Autonomous Agents
• If pedestrians take damage, they attack whoever
  is responsible
• Etc.

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more about Autonomous Agents

• Can act independently, possibly react dynamically
  to situations
• Guard AIs in Deus Ex and Thief
• Cars and Pedestrians in GTA3
• The Bat in Adventure
• Special properties
• Emergence without direct player intervention
• Make the world feel alive
• Create dynamic situations

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Creating Emergence by Adding Indirect Connections

• Emergence fails to happen when Mechanics arent
  indirectly connected
• Emergence can be created by adding more indirect
  connections making the Mechanics listen to
  each other
• Guard with torch slips on oil puddle ?
• Guard falls to the ground
• Nothing else happens

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Creating Emergence by Adding Indirect Connections

• Emergence fails to happen when Mechanics arent
  connected
• Emergence can be created by adding more
  connections making the Mechanics listen to
  each other
• Guard with torch slips on oil puddle ?
• Guard falls to the ground ?
• Guard drops torch ?
• Torch ignites oil puddle
• lets talk more about connecting Mechanics

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The Tactical Shooter Example

• Indirectly Connected Game Mechanics
• Gas barrels leak poison when ruptured
• Poison kills enemies
• Bullets Kill enemies, and Rupture gas barrels
• Weapons Fire bullets when dropped
• Enemies Fire bullets, and Drop weapons on death

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Visualizing All Mechanics
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-1 Mechanic
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-2 Mechanics
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Getting Mechanics to Connect

• Again, it helps to have a rules oriented approach
• Its tempting to spam the world with Mechanics,
  to pile them on
• Mechanics are independent, but indirectly
  connected
• Some Mechanics are more highly connected
• How do you get the best return on your
  investment?
• Choose Mechanics that have relationships to each
  other

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Example from DXIWChoosing Where to Invest

• Prismatic Resonator Biomod
• Fewer Indirect Connections
• Beam Triggers (3 types)
• Bot Domination Biomod
• More Indirect Connections
• All robots (8 types), Cameras, Turrets,
  Spiderbombs
• Bots are improvisationally useful for combat,
  door opening, setting traps, etc
• Players started using spiderbombs to open doors

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Player Improvisation

• Players Unlocked Doors with Spiderbombs
• Indirectly Connected Game Mechanics
• Spiderbombs
• Spawn Spiderbots
• Spiderbots
• Obey All Bot Rules
• Susceptible to Bot Domination
• Susceptible to EMP
• Explode If Damaged Post-EMP
• Bot Domination
• Possess Bots
• EMP Bots Post-Ejection
• Doors
• Can Be Locked/Lockpicked
• Destroyed By Explosions

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Player Improvisation
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Invest in Related Mechanics

• If youve already got these Mechanics
• Flamethrower can catch enemies on fire
• Burning enemies can catch furniture on fire
• Add more elements and Mechanics having to do with
  fire, e.g.
• Fire extinguishers
• Oil puddles
• Dynamite
• Candles
• Water arrows

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Supporting Technology

• Takeaways
• Some technology supports the implementation of
  emergence better than others
• Need to work with technologists to evaluate your
  technology status

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Supporting Technology

• Explicitly hard-coded Mechanics are messy and
  difficult to support
• You might forget to implement one of them

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Supporting Technology

• The Stimulus System is a generalized way for
  objects to listen to each other
• You can describe objects intuitively

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Supporting Technology

• Easier to create and modify connected Mechanics
• More reliable and likely to create
  improvisational emergence

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Ion Storms Supporting Technology

• Stimulus System
• Generalized channel for objects to listen to each
  other
• Dont have to explicitly hard-code Mechanics
• Property System Object Hierarchy
• Quick and easy creation and editing of objects
• Scripting System
• Quick and easy to describe resulting behaviors
• Oil puddle When I receive fire stim, turn into
  a fire puddle

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Populating the world with Mechanics

• For Mechanics to connect, they typically have to
  exist in physical proximity to each other.
• How rich is your world with Mechanics? E.g.
  how many gas barrels exist in your world?
• How often are the connected Mechanics in
  proximity to each other? E.g. do you ever
  place guards near gas barrels?

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Examples of World Population from Thief

• Negative example
• Fire elementals that re-light torches when guards
  are nearby in Thief
• Good idea, but Fire elementals and Guards /
  Torches were never in the same levels

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Examples of World Population from Thief

• Positive example
• Player shoots arrow at a candle to knock it over
  ? arrow misses and hits metal door instead ?
  nearby guard hears sound and comes to investigate
• Physical surface, Sound Propagation, and Lighting
  house Mechanics in Thief
• ..and they populate the world exhaustively.
• What elements already exist in your world which
  you can add Mechanics to?

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III Qualifying Emergence

• Qualitative
• Aesthetic Goals
• Meaningful Emergence
• Involving the Player

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What are your Aesthetic Goals?

• What do you hope for emergence to contribute to
  your game?
• Deus Ex Empower many emergent solutions
• Thief Creating the occasional sublimely tense
  moment of emergent challenge
• GTA3 Simulate a dynamic, responsive, living
  world Enable emergent mayhem
• All three Authoring your own experience
  (emergent narrative)

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Meaningful Emergence

• In accordance with aesthetic goals
• The player perceives the events
• Impact on gameplay experience, Not just some
  wacky outcome
• No gameplay relevance Prox mine wall climbing
• Gameplay relevance Spider bomb door unlocking
• Meaningful to the fantasy
• Violates fantasy Age of Empires sheep

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How involved is the player?

• Does the player have input into the Mechanics
  which create emergence?
• Theoretical Game There is a factory with lots of
  robots interacting emergently. If they touch
  you, you die, but they dont react. Get to the
  other side.

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Robot Factory Game
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Player Perception of Emergent Experiences

• Reactive does not require player input
• Emergent challenge a challenging situation
  that develops emergently
• E.g. the previous robot factory example
• E.g. pedestrians in GTA3 turn hostile toward
  the player

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Player Perception of Emergent Experiences

• Proactive player must provide input
• Emergent solution or Emergent strategy the
  player creates their own solution to a problem by
  leveraging their understanding of the games
  emergence
• E.g. igniting oil puddles by knocking a candle
  off a table in Thief
• E.g. player runs over pedestrian to summon
  ambulance for ambulance missions in GTA3

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IV Wrapping Up

• Design Process
• References

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Emergent Gameplay Design Process

• Aesthetic Goals
• Widening possibility space via emergent systems
• Technology Considerations
• Plan Game Systems
• Player agent(s), tools, traps, resources, etc.
• Decide where to invest, Disregard low connection
  Mechanics
• Populate world with Mechanics
• Evaluate system Dynamics
• Quantitatively
• Litmus test2nd order consequence?
• Common enough?
• Perceptible?
• Qualitatively
• Dynamics match the fantasy?
• Did you meet your aesthetic goals?
• Iterate

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References

• Various References to Emergence
• Marc LeBlancs GDC Lectures
• Rules of Play
• Book by Eric Zimmerman and Katie Salen
• Dynamics for Designers
• Will Wrights 2003 GDC Lecture
• Complexification
• Book by John L. Casti
• Emergence
• Book by Steven Johnson

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Practical Techniques for Implementing Emergent
Gameplay
Q A

• Randy Smith
• rsmith_at_ionstorm.com

Harvey Smith witchboy_at_zombieworld.com